Abstract:

Objective To establish a new electrochemical DNA sensor for determining multidrug-resistant Acinetobacter baumannii（MRAB） OXA-23 gene. Methods Polyallylamine-functionalized Pt nanostructures with long-spined sea-urchin-like morphology（Pt-LSSUs@PAA） was used to modify electrochemical DNA sensor interface. RuHex was used as a signal indicator. Using the established electrochemical DNA sensor,the differential pulse voltammetry was used to determine the presence of negatively charged phosphorus-bound RuHex electrochemical signal differences generated by OXA-23 mutant gene to be determined quantitatively. Results The sensor had good stability and reproducibility. The modification of Pt-LSSUs@PAA can increase the effective area of electrode,speed up the electron conduction rate on the surface of electrode and achieve signal amplification. The linear range of OXA-23 was 10 fmol/L-10 nmol/L. The determination limit was 3.3 fmol/L（signal-to-noise ratio was 3）,and the sensor had good specificity. Conclusions The established sensor can achieve sensitive and specific quantitative determination of OXA-23 mutant gene.

Key words: OXA-23 gene, Multidrug-resistant Acinetobacter baumannii, Polyallylamine-functionalized Pt nanostructures with long-spined sea-urchin-like morphology, DNA sensor